Electric stove or the like



Nov. 17, 1942.

R. H. PARK ELECTRIC STOVE OR THE LIKE Filed May 17, 1941 4 Sheets-Sheet 1 I nvenior. a Roberi Park,

Nov. 17 1942.

R. H. PARK ELECTRIC STOVE OR THE LIKE Filed May l7, 1941 4 Sheets-Sheet 2 NOV. 17, 1942. R, P RK 2,302,048

ELECTRIC STOVE OR THE LIKE Fi'led- May 17, 1941 4 Shee ts-Sheet 3 i Ii t \X 'Illlllillllllll R. H. PARK 2,302,048

ELECTRIC STOVE OR THE LIKE Filed May 17, 1941 4 Sheets-Sheet 4 oil a- Rainer? H. Paris,

mmw W W Patented Nov. 17, 1942 UNITED STATES PATENT OFFICE 2,302,048 ELECTRIC s'rovn on rm: mu: Robert 11. Park. Pluckemin, N. J. Application May 17', 1941, Serial No. 393,963 16 Claims. (Cl. 219-43) This invention relates to an electric device for use with portable, electrically energized mechdisclosed in my Patent 2,233,485, March 4, 1941,

wherein the heating effect of the electric current is exerted in the vessel itself, as by means of an inbuilt resistance element as disclosed in that patent. 1 herein refer to the device as a stove" in that it takes the form of a suitable table-like or, cabinet structure to receive cooking vessels. It differs from an ordinary stove in that it does not in itself embody a source of heat such as burning fuel from which heat is radiated or conducted to the vessel placed thereon, but it provides a support upon which'cooking vessels are placed as upon a stove top and whereonthey are supported during the heating operation. As will appear from the description, I provide means whereby the completion of the electric circuit can be effected only when the cooking vessel is upon the stove and the circuit is closed and interrupted only when there is ilrm mechanical engagement of the contact members of the stove with the contact studs of the portable vessel.

My invention will be well understood by reference to the following description of the illustrative embodiment thereof shown in the accompanying drawings, wherein- Fig. l is a fragmentary plan view of the stove showing a station to receive a single cooking utensil (corresponding roughly to one of the openings in a coal range or a single burner of a gas cooking stove), parts being broken away to disclose the interior construction;

Fig. 2 is a section on the line 22 of Fig. 1 on a smaller scale showing the clamping contacts in open position;

Fig; 4 is a view showing the parts after further movement to operating or cooking positions;

Fig. 5 is a fragmentary side elevation as seen from the bottom of Fig. l, but on a smaller scale than Fig. 1; and

placed Fig. 6 is a bottom plan view on a small scale of a cooking utensil.

I believe an understanding of the construction disclosed will be most readily attained if I first describe specifically the principal mechanical elements shown in the embodiment of the invention illustrated and thereafter explain the function and method of use subserved by such mechanical construction, after which further mechanical details will be described.

The"stove" herein shown takes the form of a suitable box-like or cabinet structure which, as best seen in Figs. 2, 3 and 4, has an extended table-like top 3 hereinshown as of thin sheet metal supported by a relatively heavy channel iron 10 which crosses centrally beneath the station on which the vessel is placed for cooking, this station being defined by an upstruck portion l2 of the top adapted to enter within the depending marginal fiange H on the bottom of the cooking vessel It. The vessel, as best seen in Fig. 6, has a pair of studs l8 projecting from'the bottom thereof which pass through the enlarged openings (Fig. 1) in the raised portion 12 of the s ve top to enter between electric contacts 22 an 24 disposed beneath the top which are arranged to close in studs to include ,the vessel in an electric circuit, cooking being effected by heat generated within the walls of the vessel as, in the case of ordinary household current, by means of an inbuilt resistance element connected to the studs l8, as in my patent above referred to, or in the case of current of low voltage and high amperage as in my Patent 2,012,618, August 27, 1935. Beneath the top of the stove contacts 22 and 24 for each of the studs 18 connected at opposite sides of the line respectively have a normally widely separated position, as shown in Fig. 2, to permit the vessel to be placed on the stove by a free movement of superposition with the studs l8 extending through the openings 20 and entering freely between the separated contacts, and they are adapted to be moved together to clamp the studs l8 from 0pposite sides. Preferably, as shown, these contacts have overhanging flanges which in the closed position overlie flange on the end of the stud iii to prevent withdrawal of the vessel until the jaws are again separated.

As seen in Fig. 2, the contact 22 is connected by a flexible conductor 25 to one side of a suitable source of current while the contact 24 is connected by conductors 28 and 30 to the opposite side of a source of current through a suitable switch 32 which may be of the construction disclamping relation to the their closed in the patent to McGall 1,960,020, May 22, 1934, and therefore unnecessary here to illustrate or describe in detail other than to note that it may provide a plunger 34 which, when depressed,'

closes the switch and which, when released, opens the same. The switch 32 is herein shown as mounted on a base plate 36 extending within the exterior structure of the stoveat some distance below the top 8 and having a pair of uprights 38 extending to the top adjacent the sides of the cooking station to provide end frames for some of the mechanisms by means of which the contacts 22 and 24 are movably mounted to perform functions, which mechanisms I will next describe.

The contacts 22 and 24 are herein mounted on the upper ends of generally vertical arms, mounted between their ends to swing on parallel, generally horizontal axes so that by spreading the lower ends of the arms the contacts are brought toward one another to clamp studs I8 between them. Referring to Figs. 2 and 1, the contacts Mare here shown as mounted on, although insulated from, the upstanding web of a generally u-shaped member having terminal flanges 4ll journalled on a rod or shaft 42, the ends of which pass snugly through the uprights 38, while the contacts 22 are mounted on a similar member having corresponding end flanges 44 and a central flange 46, best seen in Fig. 1. As seen in Fig. 2, the end flanges 44 have elongated openings 48 through which passes the rod or shaft 50 parallel to the shaft 42, thus permitting angular movement of the contact-supporting frame in the plane of the paper viewing Fig. 1 to permit equalization of pressure on the two studs l8 when the parts are closed, the shaft 50 fitting the central flange 46 closely but with sufficient play to permit such angular movement. The shaft as seen in Fig. 4, passes through substantially horizontal slots 52 in the uprights 38 and is normally maintained in the left-hand end of those slots, viewing Fig. 4, by means of the springs 54 (Fig. 1) connecting the ends of the shafts 42 and 50.

Links 56 and a central link 58 (shown dotted in Figs. 2. '3 and 4 because it is in fact at the nearer side of the sectional plane) connect respectively the lower ends of flanges 4t and the lower end of flange 48 to a rod 66, the ends of which are guided in the vertical slot 52 in the end members 38, these links constituting a toggle which, when straightened from the position of Fig. 2. will serve to swing the contact-carrying arms pivotally about the shafts 42 and 50 respectively to cause the contacts to approach one another.

For straightening the toggle the rod 60 has pivoted thereto a yoke 63 (Fig. 1) forming one end of an operating lever 64, the central portion of which is suspended, herein from the angle iron it, by a link 66, the lever 64 having a vertically elongated slot 68 receiving the pivot pin H! at the lower end of the link. The other end of the lever isslotted at 72 to receive a pin "M on one arm of an operating lever which is pivoted to the side of the stove at 76 and has a portion 18 projecting at the outer side of the stove to provide an actuating handle. Carried by the lower side of the lever 64 is a spring 80 which, when the lever is fully depressed to the position of Fig; 4, makes contact with the plunger 34 of switch 32 to close the latter.

I will now trace the operation of the parts through the successive positions of Figs. 2, 3 and 4. Referring to Fig. 2, it will be noted. that with moved slightly past dead center and the clamps the actuator handle 78 down, the contact-carrying arms under the weight of the actuating lever 64 and the associated parts are widely spread in the position of Fig. 2 and the vessel may be placed on the stove by a simple movement of superposition, the studs l8 passing through the large openings 20 and occupying a space between the widely spaced contacts 22 and 24. Now if the actuator handle 18 is raised, lever 64 will be rocked counterclockwise about pivot 10, straightening the toggle until the contacts close on the stud I8 in the position of Fig. 3.

It is to be noted, however, that in Fig. 3 the actuating lever has not yet reached its extreme of movement, the pin 14 has not reached the end of the slot 72 and the spring 80 is still spaced from the plunger 34, so that the electric circuit is not closed. On continued movement of the actuator 18 the toggle tends still further to straighten to move apart the lower end of the jaw-carrying arms, and since contact 22 is in engagement with stud l8, it will tend to turn about this point as a center, this action being permitted by movement of the shaft or rod 50in the slots 52 (Fig. 4) against the action of the springs 54, this permitting the parts to move to the position of Fig. 4 wherein the toggle has are therefore in a self-maintaining position in engagement with the stud I8 under the tension of the springs 54. During the continued movement just described consequent on the 10st motion of the shaft or rod 50 in the slots 52, the spring 80 engages and depresses the plunger 34 of switch 32 to close the circuit, which thus occurs only after the contacts have been firmly engaged with the stud. As seen in Fig. 4, in this position of the parts the pin 14 which actuates the lever 64 lie substantially in the perpendicular from its pivot to the axis of slot 12, and as a result the switch is held closed despite the fact that the spring 80 is depressed and hence is pushing up-' ward the lever 64. I

The studs is are clamped under pressure of the springs and locked by engagement of their flanges 25 beneath the contacts. The yielding mounting of contacts 22 and the provision for angular displacement provided by slots 48 equalizes the pressure on the two studs, irrespective of whether the studs are of exactly equal size or,

whether there are other minor equalities in the system.

The length of the elongated holes 48 and 52 is so limited that it is not possible to so wrack the vessel IS with the clamps closed as to cause one of the studs to come in contact with portion l2 of the stove top. Thus short circuits due to contact of the studs with a grounded stove top are precluded. 7

When cooking is completed and it is desired to remove the cooking vessel, the actuator 18 is depressed. Since the links 5658 are over .dead center and tend to hold up the rod 60 on account of the tension of the springs 54, the efiect of this is to turn lever 64 on 60 as a center, an action dimensional inpermitted by the elongation of the slot 68 suron the center 60 to move the toggle over dead center. When 60 moves past dead center in adownward direction, the effect of the springs 5! is to aid in its downward motion and the result is that the rod 60 snaps downwardly while the contact-carrying arms snap to the open position.

If nothing more than what has already been described were embodied in the mechanism, it would be possible to close the jaws with no vessel in place. Under these conditions the jaws would be energized and there would be arcing and poor contact as well as danger of short circuits from clamp jaw to frame were an attempt made to set a vessel in place. Also there would be some danger of shock with the jaws closed and energized in this manner. Accordingly I herein disclose means which make it impossible to clamp or energize the jaws except when the cooking vessel is in place, this being herein effected in the sense that the jaws cannot be clamped unless they are closed on something of the same general dimensions as the studs IS.

The mechanism employed will be best understood from Figs. 1 and 5, and it will be recalled that Fig. 1 ison a larger scale than Fig. 5. Re-' ferring particularly to Fig. 5, I have shown pivoted on the ends of rod 80 plates 82 having vertical slots 84 in which the ends of the shaft 50 are received and they are provided with a projection or shoulder 86 on the left-hand side. viewing Fig. 5. A horizontal link or plate 88 extends between the ends of shafts "and 50, engagement with the latter being through a horizontally elongated slot 90 to permit the yieldin movement of shaft 50 to the right in Fig. 1 against the action of the springs 54 during the latter portion of the clamping movement as already described. As seen in Fig. 1, this link overlies the upper end of plate 82 and is cut away or rabbeted to receive the same, and thus with the parts in the position of Fig. 5 the thicker "portion of the link presents a stop in the path of shoulder 86 as the latter moves upwardly with the rod 60. It now an attempt were made to close the clamps without the contacts I! of the cooking vessel being therebetween, the movement of the parts would not be checked by engagement of the contacts with the studs when the position of Fig. 3 is reached. Therefore, the

right hand jaw would tend to continue to move i about 50 as a center and there would be no tendency for shaft 50 to shift to the right against the action of the springs 54 and in conseouence the shoulder 86 would make contact with the thick part of the link 88 and stop further motion. The stroke of lever 64 could not be completed and the switch plunger 34 would not be actuated to close the circuit. Also since' the rod 60 would not have reached dead center. when the hand was removed from the actuator 18. the parts would return under gravity to the position of Fig. 2.

On the other hand. if the stud l8 were in position as shown in Fig. 3. shaft 5B would mov to the right as already described. swinging plate 82 clockwise, viewing Fig. 5, and permitting the shoulder 86 to pass in the reduced portion of the link 88 and the clamping cycle as previously described to be completed.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. In a device for use with a portable appliance having contacts projecting therefrom by means of which the appliance may be included in an electric circuit, a pair of opposed vertical arms, horizontal pivots on which the arms are swung between their ends, contacts carried by the upper ends of said arms adapted: when the' arms are swung to approximate the contacts swung between their ends, contacts carried by the upper ends of said arms adapted when the arms are swung to approximate the contacts to close them on the projecting contact inserted therebetween, a toggle extendingjbetween the lower ends of the arms, means for actuating the toggle, one atleast of said pivots being free to yield laterally, spring means opposing such yielding, and means to check the toggle before it reaches dead center connected to move to inoperative position on yielding movement of an arm. 1

3. In a device for use with a portable appliance having a pair of contacts projecting therefrom by means of which the appliance may be included in an electric circuit, a pair of opposed arms, each having at the sides thereof a contact to cooperate with an opposed contact on the other to engage when approximated a contact on said device inserted therebetween, pivots on which the arms are swung, the pivotal mounting of at least one of the arms being such as to permit angular motion of the sides of the arm to in an electric circuit, a pair of opposed vertical arms, horizontal pivots on which the arms are swung between their ends, contacts carried by the upper ends of said arms adapted when the arms are swung to approximate the contacts to close them on the projecting contact inserted therebetween, one at least of the pivots being free to yield laterally, and spring means opposing such yielding, means cooperating with the lower ends of the arms for spreading the same, normally tending to return to a position corresponding to approximated position of the lower ends and adapted to be retained in an extreme position under stress of said spring means when the pivot yields laterally.

5. In a device for use with a portable appliance having contacts projecting therefrom by means of which the appliance may be included in an electric circuit, a pair of opposed vertical arms, horizontal pivots on which the arms are swung between their ends, contact-s carried by the upper ends of said arms adapted when the arms are swung to approximate the contacts to close them on the projecting contact inserted therebetwen, one at least of the pivots being free to yield laterally, spring means opposing such yielding, means cooperating with the lower ends of the arms for spreading the same, normally tending to return to a position corresponding to approximated position of the lower ends and adapted to'be retained in an extreme position under stress'of said spring means when the pivot yields laterally, and a stop normally blocking movement of the spreading means to such extreme position but which is withdrawn to inoperative position by yielding of the pivot.

6. In a device for use with a portable appliance having contacts projecting therefrom by means of which the appliance may be included in an electric circuit, a pair of opposed vertical arms, horizontal pivots on which the arms are swung between their ends, contacts carried by the upper ends of said arms adapted when the arms are swung to approximate the contacts to close them on the projecting contact inserted therebetween, one at least of the pivots being arranged for slight and positively limited lateral yielding, and'spring means opposing such yielding, means cooperating with the lower ends of the arms for spreading the same, normally tending to return to a position corresponding to approximated position of the lower ends and adapted to be retained in an extreme position under stress of said spring means when the pivot yields laterally,

'7. In an electric heating device for use with a portable vessel having contacts projecting from a wall thereof by means of which the vessel may be included in a heating circuit, a pair of movable clamping jaws carrying contacts adapted to close on a contact carried by the vessel, means whereby a mechanical actuating force will move said jaws to bring the contacts to a position of approximation not further apart than the thickness of the vessel contact, said means in itself arranged to relapse and retract the jaws from said position when the force is discontinued but shiftable to a self-maintaining position under the conjoint action of such force and the mechanical resistance of the vessel contact when present and engaged by the jaws.

8. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween toinclude the device which carries the contact in an electric circuit, an actuating mechanism to impart closing movement to said clamps, one of the clamps being yieldably mounted to permit continued action of said mechanism after a grip on the contact is established, and a stop effective to stop such continued movement of said mechanism in the absence of yielding movement of the clamp resultant on engagement with such contact.

9. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween to include the device which carries the contact in an electric circuit, means for imparting closing and opening movement to the clamps, there being a lost-motion connection permitting continued movement of said means after a grip on the contact is established, a pivoted lever for actuating said means, and switch contacts for the circuit closed by said lever during such continued movement, the pivot of the lever having a lost-motion mounting permitting actuation of the lever to eifect separation of the switch contacts prior to exertion of eflective force on said clamp-moving means tending to release the clamps.

10. In combination with'a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween to include the device which carries the contact in an electric circuit, means for imparting closing and opening movement to the clamps, there being a lostmotion connection permitting continued movement of said means after a grip on the contact is established, a pivoted lever for actuating said means, switch contacts for the circuit closed by said lever during such continued movement, the pivot of the lever having a lost-motion mounting permitting actuation of the lever to efiect separation of the switch contacts prior to exertion of eifective force on said clamp-moving means tending to release the clamps, and a stop normally blocking such continued movement but movable to inoperative position when such lost motion occurs in the connection of the above recited means for imparting closing and opening movement to the clamps.

11. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween to include the device which carries the contact in an electric circuit, means for imparting closing and opening movement to the clamps, there being a lost-motion connection permitting continued movement of said means after a grip on the contact is established, a pivoted lever for actuating said means, switch contacts for the circuit closed by said lever during such continued movement, the pivot of the lever having a lost-motion mounting permitting actuation of the lever to eilect separation of the switch contacts prior to exertion of effective force on said clamp-moving means tending to release theolamps, and a manually operable member for swinging said lever which moves substantially to a dead center position to-maintain said switch contacts closed.

12. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween to include the device in an electric circuit, a switch at another point in the circuit, means for opening and closing the clamps capable of a continued movement after the clamps have engaged the contact, a pivoted lever connected at one side of its pivot to said means to actuate the clamp-closing means and having means at the other side of its pivot to operate the switch during said continued movement, said pivot being free for limited movement in one direction to permit the lever to turn about its point of connection to the closing means in the closed position of the clamp to retract said switch-operating means from the switch prior to releasing movement of the clampclosing means.

13. In combination with a pair of movably mounted clamps for closing in gripping relation to,a contact inserted therebetween to include the device in an electric circuit, a switch at another point in the circuit, means for opening and closing the clamps capable of a continued movement after the clamps have engaged the contact, a pivoted lever connected at one side of its pivot to said means to actuate the clamp-closing means and having means at the other side of its pivot to operate the switch during said continued movement, said pivot being free for limited movement in one direction to permit the lever to turn about its point of connection to the closing means in the closed position of the clamp to retract said switch-operating means from the switch prior to releasing movement of the clampclosing means, and a rotatably mounted, manually movable actuator for moving said other end of the lever toward switch-operating position and which is substantially on dead center when the switch has been closed thereby.

14. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween to include the device in an electric circuit, a switch at another point in the circuit, means for opening and closing the clamps capable oi a continued movement after the clamps have engaged the contact, a manual actuator having simple non-recurrent strokes in opposite directions to close and open the circuit respectively, and parts driven thereby moving as a unit in the closing action first to close the clamps and thereafter to close the switch during the aforesaid continued movement or the clamp-operating means, but diflerentially movable on the opening action first to open the switch before affecting the clamp-operating means.

15.1n combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween and which are normally biassed to open position wherein they are spaced one from another, an actuating dei vice for moving said clamps toward one another, which device is constructed and arranged for continued motion to a self-maintaining position if the clamps engage a contact between the same but is free to relapse if nothing is between the clamps. W

16. In combination with a pair of movably mounted clamps for closing in gripping relation to a contact inserted therebetween and normally biassed to open position, means for moving said clamps to a position wherein they would engage the contact if present and from which position they would recede ii the actuating force were removed, such means responding to the mechanical resistance of such contact if present to permit the means additionally to move under said force to a self-maintaining position.

ROBERT H. PARK. 

